Abstract:

The deformation law of tunnel structures in 4 cases, i.e., application of only pipe roof, application of only horizontal jetgrouting piles, application of pipe roof coupled with horizontal jetgrouting piles and application of no advance reinforcement, are studied by means of threedimensional elasticplastic finite element method, so as to investigate the effect of the pipe roof coupled with horizontal jetgrouting piles on the deformation of tunnel in weak strata. Conclusions drawn are as follows: 1) The horizontal jetgrouting pile method is superior in controlling crown settlement, arch spring convergence and face displacement, while the pipe roof method is superior in controlling the ground surface settlement。 2) The combination method of pipe roof and horizontal jetgrouting piles results in outstanding control of crown settlement, arch spring convergence and tunnel face horizontal displacement: the ground surface settlement is reduced by 91.3%, the crown settlement is reduced by 76.2%, and the arch spring convergence is reduced by 76.3%; the maximum ground surface settlement is 2.7 mm, the maximum crown settlement is 25 mm, the maximum arch spring convergence is 4 mm and the minimum arch spring convergence is -9.4 mm.

Key words: weak stratum, tunnel, horizontal jetgrouting pile, pipe roof, numerical simulation, settlement deformation rule